This is a repackaged version of the whole "why do people say happy new year and celebrating new year's eve, there is nothing special about any specific day". Like, come on. It's just something people say. It's not important.

Also it is kind of a remnant of older times when the year changing actually did matter a lot for various reasons, especially for farmers, it wasn't like now where for most people every day of every year isn't special for any reason.